The AXE GREEN LIT NOCKS FOR AX405 CROSSBOLTS are a reliable and efficient lighting system designed specifically for crossbow strings. These nocks feature a super-bright LED that is activated by the forward movement of the string, providing a clear and consistent light source. The metal injection molded construction ensures a secure fit on the crossbow's string, while the audible click when properly secured provides added peace of mind. With over 20 hours of battery life, these nocks can be reused multiple times, making them an affordable option for crossbow enthusiasts. Fast shipping ensures that you'll have these nocks in hand quickly, so you can get back to your practice sessions or hunting trips.Product Features and Specifications: Weight: 44 grains Diameter: .166 Battery Life: 20+ hours